Category: Soft Tissue Sarcoma

Soft Tissue Sarcoma Stages

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After someone is diagnosed with a soft tissue sarcoma, doctors will try to figure out if it has spread, and if so, how far. This process is called staging. The stage of a cancer describes how much cancer is in the body. It helps determine how serious the cancer is and how best to treat it. Doctors also use cancer’s stage when talking about survival statistics.

The stages of soft tissue sarcomas range from stages I (1) through IV (4). As a rule, the lower the number, the less cancer has spread. A higher number, such as stage IV, means cancer has spread more. And within a stage, an earlier letter means a lower stage. Although each person’s cancer experience is unique, cancers with similar stages tend to have a similar outlook and are often treated in much the same way.

How is the stage determined?

The staging system most often used for soft tissue sarcomas is the American Joint Committee on Cancer (AJCC) TNM system, which is based on 4 key pieces of information:

  • The extent of the tumor (T): How large is the cancer?
  • The spread to nearby lymph nodes (N): Has cancer spread to nearby lymph nodes?
  • The spread (metastasis) to distant sites (M): Has cancer spread to distant organs such as the lungs?
  • The grade (G) of cancer: How much do the sarcoma cells look like normal cells?

Grade

The grade is partly used to determine the stage of a sarcoma. The staging system divides sarcomas into 3 grades (1 to 3). The grade of a sarcoma helps predict how rapidly it will grow and spread. It’s useful in predicting a patient’s outlook and helps determine treatment options.

The grade of a sarcoma is determined using a system known as the French or FNCLCC system, and is based on 3 factors:

  • Differentiation: Cancer cells are given a score of 1 to 3, with 1 being assigned when they look a lot like normal cells and 3 is used when the cancer cells look very abnormal. Certain types of sarcoma are given a higher score automatically.
  • Mitotic count: How many cancer cells are seen dividing under the microscope; given a score from 1 to 3 (a lower score means fewer cells were seen dividing)
  • Tumor necrosis: How much of the tumor is made up of dying tissue; given a score from 0 to 2 (a lower score means there was less dying tissue present).

Each factor is given a score, and the scores are added to determine the grade of the tumor. Sarcomas that have cells that look more normal and have fewer cells dividing are generally placed in a low-grade category. Low-grade tumors tend to be slow-growing, slower to spread, and often have a better outlook (prognosis) than higher-grade tumors. Certain types of sarcoma are automatically given higher differentiation scores. This affects the overall score so much that they are never considered low grade. Examples of these include synovial sarcomas and embryonal sarcomas. Here’s what the grade numbers mean:

GX: The grade cannot be assessed (because of incomplete information).

Grade 1 (G1): Total score of 2 or 3

Grade 2 (G2): Total score of 4 or 5

Grade 3 (G3): Total score of 6, 7 or 8

Defining TNM

There are different staging systems for soft-tissue sarcomas depending on where the cancer is in the body.

  • Head and neck
  • Trunk and extremities (arms and legs)
  • Abdomen and thoracic (chest) visceral organs
  • Retroperitoneum

Numbers or letters after T, N, and M provide more details about each of these factors. Higher numbers mean the cancer is more advanced. Once a person’s T, N, and M categories have been determined, this information is combined in a process called stage grouping to assign an overall stage. Of the 4 main locations, only 2 (Trunk and Extremities and Retroperitoneum) have stage groupings. For more information see Cancer Staging.

The staging system in the table below uses the pathologic stage (also called the surgical stage). It is determined by examining tissue removed during an operation. Sometimes, if surgery is not possible right away or at all, cancer will be given a clinical stage instead. This is based on the results of a physical exam, biopsy, and imaging tests. The clinical-stage will be used to help plan treatment. Sometimes, though, cancer has spread further than the clinical stage estimates, and may not predict the patient’s outlook as accurately as a pathologic stage.

The system described below is the most recent AJCC system, effective January 2018. Cancer staging can be complex, so ask your doctor to explain it to you in a way you understand.

Trunk and Extremities Sarcoma Stages

AJCC stage Stage grouping Trunk and Extremities Sarcoma Stage description*
IA T1

N0

M0

G1 or GX

The cancer is 5 cm (2 inches) or smaller (T1).

It has not spread to nearby lymph nodes (N0) or to distant sites (M0). The cancer is grade 1 (G1) or the grade cannot be assessed (GX).

IB T2, T3, T4

N0

M0

G1 or GX

 

The cancer is:

  • Larger than 5 cm but not more than 10 cm (T2) OR
  • Larger than 10cm but not more than 15 cm (T3) OR
  • Larger than 15 cm (T4).

It has not spread to nearby lymph nodes (N0) or to distant sites (M0). The cancer is grade 1 (G1) or the grade cannot be assessed (GX).

 

II

T1

N0

M0

G2 or G3

The cancer is 5 cm (2 inches) or smaller (T1).

It has not spread to nearby lymph nodes (N0) or to distant sites (M0). The cancer is grade 2 (G2) or grade 3 (G3).

IIIA

 

T2

N0

M0

G2 or G3

The cancer is larger than 5 cm (2 inches) but not more than 10 cm (T2).

It has not spread to nearby lymph nodes (N0) or to distant sites (M0). The cancer is grade 2 (G2) or grade 3 (G3).

IIIB T3 or T4

N0

M0

G2 or G3

The cancer is:

  • Larger than 10 cm but not more than 15 cm (T3) OR
  • Larger than 15 cm (T4).

It has not spread to nearby lymph nodes (N0) or to distant sites (M0). The cancer is grade 2 (G2) or grade 3 (G3).

IV Any T

N1

M0

Any G

The cancer is any size (Any T) AND it has spread to nearby lymph nodes (N1).

It has not spread to distant sites (M0). It can be any grade.

OR
Any T

Any N

M1

Any G

The cancer is any size (Any T) AND it has spread to nearby lymph nodes (N1).

It has spread to distant sites such as the lungs (M1). It can be any grade.

*The following categories are not listed in the table above:

  • TX: Main tumor cannot be assessed due to lack of information.
  • T0: No evidence of a primary tumor.
  • NX: Regional lymph nodes cannot be assessed due to lack of information.

Retroperitoneum Sarcoma Stages

AJCC stage Stage grouping Retroperitoneum Sarcoma Stage description*
IA T1

N0

M0

G1 or GX

The cancer is 5 cm (2 inches) or smaller (T1).

It has not spread to nearby lymph nodes (N0) or to distant sites (M0). The cancer is grade 1 (G1) or the grade cannot be assessed (GX).

IB T2, T3, T4

N0

M0

G1 or GX

The cancer is:

  • Larger than 5 cm but not more than 10 cm OR
  • Larger than 10 cm but not more than 15 cm (T3) OR
  • Larger than 15 cm (T4).

It has not spread to nearby lymph nodes (N0) or to distant sites (M0). The cancer is grade 1 (G1) or the grade cannot be assessed (GX).

 

II

T1

N0

M0

G2 or G3

The cancer is 5 cm (2 inches) or smaller (T1).

It has not spread to nearby lymph nodes (N0) or to distant sites (M0). The cancer is grade 2 (G2) or grade 3 (G3).

IIIA

 

T2

N0

M0

G2 or G3

The cancer is larger than 5 cm (2 inches) but not more than 10 cm (T2).

It has not spread to nearby lymph nodes (N0) or to distant sites (M0). The cancer is grade 2 (G2) or grade 3 (G3).

IIIB T3 or T4

N0

M0

G2 or G3

The cancer is:

  • Larger than 10 cm but not more than 15 cm (T3) OR
  • Larger than 15 cm (T4).

It has not spread to nearby lymph nodes (N0) or to distant sites (M0). The cancer is grade 2 (G2) or grade 3 (G3).

OR
Any T

N1

M0

Any G

The cancer is any size (Any T) AND it has spread to nearby lymph nodes (N1).

It has not spread to distant sites (M0). It can be any grade.

IV Any T

Any N

M1

Any G

The cancer is any size (Any T) AND it has spread to nearby lymph nodes (N1).

It has spread to distant sites such as the lungs (M1). It can be any grade.

*The following categories are not listed in the table above:

  • TX: Main tumor cannot be assessed due to lack of information.
  • T0: No evidence of a primary tumor.
  • NX: Regional lymph nodes cannot be assessed due to lack of information.

Signs and Symptoms of Soft Tissue Sarcomas

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About half of soft tissue sarcomas start in an arm or leg. Most people notice a lump that’s grown over time (weeks to months). The lump may or may not hurt.

When sarcomas grow in the back of the abdomen (the retroperitoneum), the symptoms often come from other problems the tumor is causing. For instance, they may cause blockage or bleeding of the stomach or bowels. They can press on nerves, blood vessels, or nearby organs. They can grow large enough for the tumor to be felt in the belly. Sometimes the tumors cause pain. About 4 of 10 sarcomas begin in the abdomen (belly).

In rare cases, sarcomas can start in the chest or in the head or neck.

If you have any of these problems, see a doctor right away:

  • A new lump or a lump that’s growing (anywhere on your body)
  • Abdominal pain that’s getting worse
  • Blood in your stool or vomit
  • Black, tarry stools (when bleeding happens in the stomach or bowels, the blood can turn black as it’s digested, and it might make the stool very black and sticky)

These symptoms are more often caused by things other than sarcoma, but they still need to be checked out by a doctor.

Can Soft Tissue Sarcomas Be Found Early?

People who have a strong family history of soft tissue sarcomas or who have had other cancers when they were young, might want to talk to a doctor about the benefits and disadvantages of genetic testing. The test results should always be explained by a genetic counselor or a specially trained doctor who can interpret the results and advise high-risk patients about the need for early cancer detection tests.

Families with a history of certain inherited conditions caused by defects in certain genes have an increased risk of soft tissue sarcomas. The changed (mutated) genes can be detected by genetic testing, so family members should discuss this option with their doctors. They should also see their doctor right away if they notice any lumps or growths. (The inherited conditions linked to soft tissue sarcoma are covered in  Risk Factors for Soft Tissue Sarcomas)

No screening tests and exams are recommended for people who have no family history of sarcoma or other sarcoma risk factors. For these people, the best approach to early detection is to tell their health care provider about any unexplained lumps or growths or other symptoms that may be caused by a soft tissue sarcoma.

Tests for Soft Tissue Sarcomas

If you have signs or symptoms that suggest you might have a soft tissue sarcoma, the doctor will likely need to do tests to find out if you have cancer.

Medical history and physical exam

The doctor will ask about your medical history, including your family history, to learn if you have any possible risk factors. You will also be asked about your symptoms, such as when they started and how long you’ve had them.

Imaging tests

Imaging tests use sound waves, x-rays, magnetic fields, or radioactive substances to create pictures of the inside of your body. Imaging tests may be done for a number of reasons, such as:

  • To look at suspicious areas that might be cancer,
  • To see if, and how far, cancer has spread
  • To help determine if treatment is working

Plain x-ray

A regular x-ray of the area with the lump may be the first test ordered. A chest x-ray may be done after you are diagnosed to see if the sarcoma has spread to the lungs.

CT (computed tomography) scans

A CT scan uses x-rays to make detailed cross-sectional images of your body. This test is often done if the doctor suspects a soft tissue sarcoma in the chest, abdomen (belly), or the retroperitoneum (the back of the abdomen). This test is also used to see if the sarcoma has spread to the lungs, liver, or other organs.

CT scans might be used to guide a biopsy needle into a tumor inside the body — the chest or abdomen, for example. This is called a CT-guided needle biopsy. (See below for more on biopsy.) You lie on the CT scanning table while a radiologist moves a biopsy needle toward the tumor. CT scans are repeated until the doctors are sure the needle is within the tumor.

MRI (magnetic resonance imaging)

MRI uses radio waves and strong magnets instead of x-rays to take pictures of the body. MRI scans are often part of the work-up of any tumor that could be a sarcoma. They’re often better than CT scans in evaluating sarcomas in the arms or legs.

MRI provides a good picture of the extent of the tumor. It can show your health care team many things about the tumor, like where it is, how big it is, and sometimes even the type of tissue it comes from (like bone, fat, or muscle). MRIs are also very helpful in examining the brain and spinal cord.

Ultrasound

Ultrasound uses sound waves and their echoes to produce pictures of parts of the body. A small instrument called a transducer sends out sound waves and picks up the echoes as they bounce off the organs. A computer then converts the echoes into an image on a screen.

Ultrasound may be done before a biopsy to see if a lump is a cyst, meaning if it has fluid in it and is likely not cancer, or if it’s solid and more likely a tumor. This test is often not needed if a CT or MRI was done.

PET (positron emission tomography) scan

PET scans use a form of radioactive sugar that’s put into the blood. Because cancers use glucose (sugar) at a higher rate than normal tissues, the radioactivity collects in cancer. A scanner can then spot the radioactive deposits.

A PET scan is useful when your doctor thinks cancer has spread but doesn’t know where. It can be used instead of many different x-rays because it scans your whole body. Often the PET scan is used with a CT scan (called a PET/CT scan). This helps decide if changes seen on the CT scan are cancer or something else. PET isn’t often used for sarcoma, but it can be helpful in some cases.

Biopsy

If a soft tissue sarcoma is suspected based on exams and imaging tests, a biopsy is needed to know for sure that it’s sarcoma and not another type of cancer or a benign (not cancer) disease. In a biopsy, the doctor takes out a small piece of the tumor. This tissue is looked at under a microscope and other lab tests may be done as well.

Several types of biopsies are used to diagnose sarcomas. Doctors experienced with these tumors will choose one, based on the size and location of the tumor. Most prefer to use a fine needle aspiration or a core needle biopsy as the first step. See Testing Biopsy and Cytology Specimens for Cancer to learn more about the types of biopsies, how the tissue is used in the lab to diagnose cancer, and what the results may show.

You might want to ask about your surgeon’s experience doing biopsies. Proper biopsy technique is a very important part of successfully treating soft tissue sarcomas. An improper biopsy can lead to tumor spread and problems removing the tumor later on.

Soft Tissue Sarcoma Risk Factors

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sarcoma

A sarcoma risk factor is anything that changes your chance of getting a disease like cancer. Different cancers have different risk factors. For example, unprotected exposure to strong sunlight is a risk factor for skin cancer. Smoking is a risk factor for cancers of the lung, and many other cancers. But risk factors don’t tell us everything. Having a risk factor, or even many doesn’t mean that you will get cancer. Also, many people get cancer without having a risk factor.

Injury and lifestyle factors such as smoking, diet, and exercise are NOT linked to sarcoma risk factors. But the injury issue has caused some confusion in the past. One reason is that an injured area might swell. That swelling could look like a tumor, but it isn’t one. Also, when you are injured, the pain may draw your attention to the injured area. A doctor may check the area, and x-rays or other imaging studies may be done. This can make it more likely that any sarcoma risk factor that’s there will be discovered, even though it may have been there for some time.

Still, scientists have found a few risk factors that make a person more likely to develop soft tissue sarcoma:

Radiation is given to treat other cancers

Radiation exposure accounts for less than 5% of sarcoma risk factor. But patients might develop sarcomas from radiation given to treat other cancers, like breast cancer or lymphoma. The sarcoma often starts in the part of the body that was treated with radiation. The average time between the radiation treatments and the diagnosis of a sarcoma is about 10 years.

Radiation therapy techniques have improved steadily over several decades. Treatments now target cancers more precisely, and more is known about selecting radiation doses. These advances are expected to reduce the number of cancers caused by radiation therapy. But because these cancers take so long to develop, the results of these changes may not be seen for a long time. Still, radiation therapy is used only when its benefits (improved survival rate and relief of symptoms) outweigh its risks. To learn more, see Second Cancers in Adults.

Family cancer syndromes

Family cancer syndromes are disorders caused by gene defects (mutations) that people are born with (often inherited from a parent) that are linked to a high risk of getting certain cancers. Some family cancer syndromes increase a person’s risk of developing soft tissue sarcomas.

Neurofibromatosis

Neurofibromatosis is also known as von Recklinghausen disease. It usually runs in families and causes many benign (not cancer) tumors that form in nerves under the skin and in other parts of the body (These are called neurofibromas.) It’s caused by a defect (mutation) in genes called NF1 and NF2. About 5% of people with neurofibromatosis will develop a sarcoma in a neurofibroma.

Gardner syndrome

Gardner syndrome is a disease caused by defects in the APC gene. This syndrome is a type of familial adenomatous polyposis (FAP), and people with it get many polyps in the colon (and intestines) and have a high risk of getting colon cancer. It also causes problems outside the colon, including desmoid tumors. (These are discussed in What Is a Soft Tissue Sarcoma? )

Li-Fraumeni syndrome

Li-Fraumeni syndrome is caused by inherited defects in the TP53 gene. People affected by this syndrome have a high risk of cancer, such as breast cancer, brain tumors, leukemia, and sarcoma. Still, only 10 to 20 out of 100 people with Li-Fraumeni syndrome will develop a soft tissue sarcoma. People with this syndrome are sensitive to the cancer-causing effects of radiation. So if they have cancer that’s treated with radiation, they have a very high chance of developing new cancer in the part of the body that was treated.

Retinoblastoma

Retinoblastoma is an eye cancer in children that can be caused by defects in the RB1 gene. Children with this gene defect also have a higher risk of developing bone or soft tissue sarcoma, especially if the retinoblastoma was treated with radiation.

Werner syndrome

Werner syndrome is caused by defects in the RECQL2 gene. Children with this syndrome have problems like those seen in the elderly. These include cataracts, skin changes, and clogged heart arteries (arteriosclerosis) which can lead to heart attacks. They also have an increased risk of cancer, including soft tissue sarcoma.

Gorlin syndrome

Gorlin syndrome is also called nevoid basal cell carcinoma syndrome (NBCCS). It’s caused by defects in the PTCH1 gene. People with this syndrome have a high risk of developing many basal cell skin cancers. They also have an increased risk of fibrosarcoma and rhabdomyosarcoma.

Tuberous sclerosis

Tuberous sclerosis can be caused by a defect in the TSC1 and/or TSC2 gene. People with this syndrome often have seizures and learning problems. They get benign (not cancer) tumors in many different organs. They also have kidney problems, often along with a kidney tumor called an angiomyolipoma. People with tuberous sclerosis have an increased risk of rhabdomyosarcoma.

Damaged lymph system

Lymph is a clear fluid containing immune system cells that are carried throughout the body by a series of lymph vessels. These vessels connect lymph nodes (small bean-shaped collections of immune system cells). When lymph nodes have been removed or damaged by radiation therapy, lymph fluid can build up and cause swelling. This is called lymphedema.

Lymphangiosarcoma (a malignant (cancer) tumor that develops in lymph vessels) is a very rare complication of chronic lymphedema.

Chemicals

Exposure to vinyl chloride (a chemical used in making plastics) is a risk factor for developing sarcomas of the liver, but it hasn’t been proven to cause soft tissue sarcomas. Arsenic has also been linked to a type of liver sarcoma but not soft tissue sarcoma. Exposure to dioxin and to herbicides that contain phenoxy acetic acid at high doses (such as might occur in people who work on farms) may also be risk factors, but this isn’t known for certain. There’s no evidence that herbicides (weed killers) or insecticides, at levels encountered by the general public, cause sarcomas.

What Causes Soft Tissue Sarcoma?

Scientists don’t know exactly what causes most soft tissue sarcomas, but they have found some risk factors that can make a person more likely to develop these cancers. And research has shown that some of these risk factors affect the genes in cells in the soft tissues.

Researchers have made great progress in understanding how certain changes in DNA (pieces of genes) can cause normal cells to become cancer. DNA carries the instructions for nearly everything our cells do. We usually look like our parents because they are the source of our DNA. But DNA affects more than just the way we look.

The DNA is made of genes. Genes carry the recipes for making proteins, the molecules that control all cell functions. Some genes contain instructions for proteins that control when our cells grow and divide.

  • Certain genes that promote cell division are called oncogenes.
  • Others that slow down cell division or cause cells to die at the right time are called tumor suppressor genes.

Cancers can be caused by DNA mutations (defects) that turn on oncogenes or turn off tumor suppressor genes.

Many family cancer syndromes have been found in which inherited DNA mutations cause a very high risk of developing breast, colon, kidney, eye, or other cancers. Some of these syndromes are also linked to an increased risk of developing soft tissue sarcomas. (These syndromes were noted in Risk Factors for Soft Tissue Sarcomas) The syndromes are caused by defects (mutations) in genes that can be inherited (passed on) from a parent. Some of these gene defects can be found through testing. For more on this, see Family Cancer Syndromes and Genetics and Cancer.

DNA mutations in soft tissue sarcoma are common. But they’re usually acquired during life rather than having been inherited before birth. Acquired mutations may result from exposure to radiation or cancer-causing chemicals. In most sarcomas, they occur for no apparent reason.

Researchers still don’t know why most soft tissue sarcomas develop in people who have no apparent risk factors.

Soft Tissue Sarcoma

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sarcoma

If you have a soft tissue sarcoma or are close to someone who does, knowing what to expect can help you cope. Here you can find out all about soft tissue sarcomas in adults, including risk factors, symptoms, how they’re found, and how they’re treated.

Cancer starts when cells start to grow out of control. Cells in nearly any part of the body can become cancer and can spread to other areas.

There are many types of soft tissue tumors, and not all of them are cancerous. Many benign tumors are found in soft tissues. The word benign means they’re not cancer. These tumors can’t spread to other parts of the body. Some soft tissue tumors behave in ways between cancer and non-cancer. These are called intermediate soft tissue tumors.

When the word sarcoma is part of the name of a disease, it means the tumor is malignant (cancer). A sarcoma is a type of cancer that starts in tissues like bone or muscle. Bone and soft tissue sarcomas are the main types of sarcoma. Soft tissue sarcomas can develop in soft tissues like fat, muscle, nerves, fibrous tissues, blood vessels, or deep skin tissues. They can be found in any part of the body. Most of them start in the arms or legs. They can also be found in the trunk, head and neck area, internal organs, and the area in the back of the abdominal (belly) cavity (known as the retroperitoneum). Sarcomas are not common tumors.

Sarcomas that most often start in bones, such as osteosarcomas, and sarcomas that are most often seen in children, such as the Ewing Family of Tumors and Rhabdomyosarcoma, are not covered here.

Types of soft tissue sarcoma

There are more than 50 different types of soft tissue sarcomas. Some are quite rare, and not all are listed here:

  • Adult fibrosarcoma usually affects fibrous tissue in the legs, arms, or trunk. It’s most common in people between the ages of 20 and 60, but can occur in people of any age, even in infants.
  • Alveolar soft part sarcoma is rare cancer that mostly affects young adults. These tumors most commonly start in legs.
  • Angiosarcoma can start in blood vessels (hemangiosarcomas) or in lymph vessels (lymphangiosarcomas). These tumors sometimes start in a part of the body that has been treated with radiation Angiosarcomas are sometimes seen in the breast after radiation therapy and in limbs with lymphedema.
  • Clear cell sarcoma is rare cancer that often starts in tendons of the arms or legs. Under the microscope, it has some features of malignant melanoma, a type of cancer that starts in pigment-producing skin cells. How cancers with these features start in parts of the body other than the skin is not known.
  • Desmoplastic small round cell tumor is a rare sarcoma of teens and young adults. It’s found most often in the abdomen (belly).
  • Epithelioid sarcoma most often starts in tissues under the skin of the hands, forearms, feet, or lower legs. Teens and young adults are often affected.
  • Fibromyxoid sarcoma, low-grade is slow-growing cancer that most often starts as a painless growth in the trunk or arms and legs (particularly the thigh). It is more common in young to middle-aged adults. It is sometimes called an Evans’ tumor.
  • Gastrointestinal stromal tumor (GIST) is a type of sarcoma that starts in the digestive tract. See Gastrointestinal Stromal Tumor (GIST) for more details.
  • Kaposi sarcoma is a type of sarcoma that starts in the cells lining lymph or blood vessels. See Kaposi Sarcoma.
  • Leiomyosarcoma is a type of cancer that starts in smooth muscle tissue. These tumors often start in the abdomen, but they can also start in other parts of the body, such as the arms or legs, or in the uterus (see Uterine Sarcoma).
  • Liposarcomas are malignant tumors of fat tissue. They can start anywhere in the body, but they most often start in the thigh, behind the knee, and inside the back of the abdomen (belly). They occur mostly in adults between 50 and 65 years old.
  • Malignant mesenchyma is a rare type of sarcoma that shows features of fibrosarcoma and features of at least 2 other types of sarcoma.
  • Malignant peripheral nerve sheath tumors include neurofibrosarcomasmalignant schwannomas, and neurogenic sarcomas. These are sarcomas that start in the cells that surround a nerve.
  • Myxofibrosarcomas, low-grade are most often found in the arms and legs of elderly patients. They are most common in or just under the skin and there might be more than one tumor.
  • Rhabdomyosarcoma is the most common type of soft tissue sarcoma seen in children. See Rhabdomyosarcoma.
  • Synovial sarcoma is a malignant tumor of the tissue around joints. The most common locations are the hip, knee, ankle, and shoulder. This tumor is more common in children and young adults, but it can occur in older people.
  • Undifferentiated pleomorphic sarcoma (UPS) was once called malignant fibrous histiocytoma (MFH). It’s most often found in the arms or legs. Less often, it can start inside at the back of the abdomen (the retroperitoneum). This sarcoma is most common in older adults. It mostly tends to grow into other tissues around the place it started, but it can spread to distant parts of the body.

Intermediate soft tissue tumors

These may grow and invade nearby tissues and organs, but they tend to not spread to other parts of the body.

  • Dermatofibrosarcoma protuberans is a slow-growing cancer of the fibrous tissue beneath the skin, usually in the trunk or limbs. It grows into nearby tissues but rarely spreads to distant sites.
  • Fibromatosis is the name given to fibrous tissue tumor with features in between fibrosarcoma and benign tumors such as fibromas and superficial fibromatosis. They tend to grow slowly but, often, steadily. They are also called desmoid tumors, as well as the more scientific name musculoaponeurotic fibromatosis or just aggressive fibromatosis. They rarely, if ever, spread to distant sites, but they do cause problems by growing into nearby tissues. They can sometimes be fatal. Some doctors consider them a type of low-grade fibrosarcoma, but others believe they are a unique type of fibrous tissue tumor. Certain hormones, like estrogen, make some desmoid tumors grow. Anti-estrogen drugs are sometimes useful in treating desmoids that cannot be completely removed by surgery.
  • Hemangioendothelioma is a blood vessel tumor that is considered low-grade cancer (meaning it grows slowly and is slow to spread). It does grow into nearby tissues and sometimes can spread to distant parts of the body. It may start in soft tissues or in internal organs, such as the liver or lungs.
  • Infantile fibrosarcoma is the most common soft tissue sarcoma in children under one year of age. It tends to be slow-growing and is less likely to spread to other organs than adult fibrosarcomas.
  • Solitary fibrous tumors are most often not cancer (benign) but can be cancer (malignant). Some start in the thigh, underarm, and pelvis. They can also start in the tissue surrounding the lung (called the pleura). Many tumors that were once called hemangiopericytomas are now considered solitary fibrous tumors.

Benign soft tissue tumors

Many benign tumors, or tumors that are not cancer, can start in soft tissues. These include:

  • Elastofibromas: benign tumors of fibrous tissue
  • Fibromas: benign tumors of fibrous tissue
  • Fibrous histiocytomas: benign tumors of fibrous tissue
  • Glomus tumors: benign tumors that occur near blood vessels
  • Granular cell tumors: usually benign tumors in adults that often start in the tongue but can be found almost anywhere in the body
  • Hemangiomas: benign tumors of blood vessels
  • Hibernomas: benign tumors of fat tissue
  • Lipomas: very common benign tumors of fat tissue
  • Leiomyomas: benign tumors of smooth muscle that can be found anywhere in the body but are very common in the walls of the uterus where they are known as fibroids
  • Lipoblastomas: benign fat tissue tumors were most often seen in children
  • Lymphangiomas: benign tumors of lymph vessels
  • Myxomas: benign tumors that usually are in muscles but do not start from muscle cells
  • Neurofibromas: tumors of nerve tissue that are usually benign. Neurofibromas of large nerves, such as those in the upper arms or neck can become cancer. Neurofibromas are very common in people with an inherited condition called neurofibromatosis (also called von Recklinghausen disease) They’re much less common in people without this condition.
  • Neuromas: benign tumors of nerves that can be painful
  • PEComas: a family of tumors made up of abnormal cells called perivascular epithelial cells. Although most of these tumors are benign, some rare PEComas are malignant (cancer). The most common of these tumors are angiomyolipoma and lymphangioleiomyoma. Angiomyolipoma is a benign tumor that most often affects the kidney. Lymphangioleiomyomatosis (or LAM) is a rare disease of women in which the many lymphangioleiomyoma tumors grow into the lung tissue and interfere with lung function.
  • Rhabdomyomas: benign tumors of skeletal and heart muscle
  • Schwannomas (neurilemmomas): benign tumors of the cells that coat nerves
  • Tenosynovial giant cell tumors (also called nodular tenosynovitis): benign tumors of joint tissue

Spindle cell tumors

Spindle cell tumor and spindle cell sarcoma are descriptive names used because the cells look long and narrow under the microscope. Spindle cell tumor is not a specific diagnosis or a specific type of cancer. The tumor may be a sarcoma, or it can be sarcomatoid — meaning another type of tumor (like a carcinoma) that looks like a soft tissue sarcoma under the microscope.

Tumor-like conditions of soft tissue

Some changes in soft tissues are caused by inflammation or injury and can form a mass that looks like a soft tissue tumor. Unlike a real tumor, they don’t come from a single abnormal cell, they have limited ability to grow or spread to nearby tissues and never spread through the bloodstream or lymph system to other parts of the body. Nodular fasciitis and myositis ossificans are 2 examples that affect tissues under the skin and muscle tissues, respectively.